South Koreans looking to study in the United States are turning to “digital undertakers” to scrub their online footprint clean before applying for visas, as President Donald Trump’s administration seeks to significantly tighten its social media vetting.Last Friday, the US Embassy in Seoul said it would resume receiving visa applications for students and those on exchange programmes – but applicants would have to give it access to their social media accounts.“All applicants for F, M or J...